Shoe and insole



March 25, 1930. P. F. w. c. KRIPPENDORF 1,

SHOE AND INSOLE I Filed Jan. 23. 1926 Patented Mar. 25, 1930' UNITEDSTATES PATENT OFFICE- PAUL F. W. C. KRIPPENDORF, OF LYNN, IllTASS ACHUSETTS, ASSIGNOR T FITZ-EMPIRE DOUBLE PIVOT LAST COMPANY, OF AUBURN,MAINE, A CORPORATION OF MAINE SHOE AND INSOLE Application filed January28, 1926; Serial No. 88,376.

This invention relates to improvements in shoes and insoles. In theembodiment selected'for illustration the invention is shown as used inthe manufacture of shoes of the welt type. It is to be understood,however, that the invention is equally applicable to the manufacture ofshoes of other types.

An object of this invention is to produce a shoe which, while retainingall the style and shapeliness characteristic of good shoemaking, will atthe same time so meet the natural requirements of a normal human footthat it will not only be extremely comfortable to wear but will alsotend to prevent development of any abnormalities, such for. example asfalling arches, and where such deformities have occurred, will tend tocorrect them.

From a study of impressions of the normal human foot in plastic materialand from considerations of the anatomy of the foot I have discoveredthat a support for the forepart of the foot, such as the inside of ashoe, should be flat for a considerable area, this area being roughlytriangular with thebase of the triangle corresponding substantially tothe ball line of a last which may be defined as a line extendingtransversely of the last a short distance (say one half inch) at therear of the line joining the anterior ends of the first and fifthmetatarsal bones. The apex of the triangle lies between the phalanges ofthe great toe and the second toe. This flat triangular area should liein a plane substantially parallel to the tread plane of the shoe, thatis, for example, the plane of the tread face of the heel extendedforwardly. The forepart area outside of this approximately triangulararea should extend upwardly and outwardly to a degree approximating theusual spring of a last.

Accordingly, in an important aspect, the presentinvention consists in ashoe the footengaging surface of the forepart of the insole of which hasa substantially fiat, triangular area lying parallel to the tread planeof the shoe. To this end, the insole of the illustrated shoe. is formedwith a substantially flat ortion in-the shape of a triangle the base 0which is substantially at the ball 50 line: of the last and the apex ofwhich lies between the great and second toes, the forepart area outsideof the triangular area from the ball line forward being directedupwardly and outwardly to an extent-substantially approximating theusual spring of a last. In this construction the surface below theanterior metatarsal arch is flat and hence ofiers no resistance to thenatural flattening of the arch as the foot is bent in walking and at thesame time prevents the flattening movement from going too far as wouldbe the case if this surface were transversely concave. Moreover, sincethe ball line of the shoe at which the bend of the toes should occur inwalking is perfectly straight, the maximum flexibility of the sole atthis line is afforded, for obviously any transverse curvature of thesole along this line would tend to stiffen the sole.

It is observable that when-the foot is pressed lightly on a flat surfacethe ends of the toes are slightly raisedfrom that surface hence, by thestructure described comprising a flat, triangular area with an upwardlyand out wardly extending margin, a support for the toes in their naturalposition is afiorded. This construction adds greatly to the comfort ofthe shoe and tends to prevent friction between the toes and the interiorof the shoe during the act of walking.

One of the principal bearing points'of the foot is at the head of thefifth metatarsal bone where it joins the cuboid bone. The

principal nerves and blood vessels of the foot run along near the outerside of the foot just inside of the bearing point referred to. In

fact, most of these nerves and blood vessels will be found tolieapproximately above a line drawn from about the center of the breastline to the outer end of theball line of the shoe. Hence, it isdesirable to avoid any pressure upon the bottom of the foot in theregion of this line which would tend to in-' terfere with the nervecontrol, blood circulating or muscular action.

In view of the foregoing and in accordance with another feature of thepresent invention the illustrated shoe is provided with a shank portionwhich extends in a straight line from about the center of the breastline to a point adjacent to the outer end of the ball line. By

\ counter portion.

thus dispensing with any longitudinal arch along this line, pressuresuch as would interfere with free action of the tendons, impedecirculation in the blood vessels, or impair the function of the nerves,is avoided.

At each side of the above-mentioned straight line it is desirable thatthe shank portion of the sole have a pronounced transverse curvature,especially at the inner side of the shank where it is important that theinsole be caused to extend well into the hollow or longitudinal arch onthe inner side of the foot soas to conform to the anatomical structureof the foot. This formation not only preserves the natural arch of thefoot and adds much to the appearance of the shoe, but also affords asupport for the shank of the foot against lateral movement in eitherdirection so that the tendency of the wearer to run the shoe over oneither side is obviated. It is desirable also to provide a pronouncedpocket for the ball of the heel. This not only contributes to thecomfort of the wearer by keeping the cushion under the heel bone whereit belongs, but also prevents any tendency of the shoe to run over atthe To obtain these results the insole of the illustrated shoe is notcut away on the inner side but has practically the full contour exceptthat, advantageously, a slight indentation or notch may be formed at theinner end of the ball line to locate the inner end of the ball line andfacilitate bending of the sole. The illustrated insole is practicallystraight, that is, nearly bilaterally symmetrical with respect to itslongitudinal axis. Hence, when it is applied to a crooked last thelongitudinal median line of the rear portion must be deflected laterallywith respect to the longitudinal median line of the forepart, so thatthe material of the insole on the inner side of the shank is caused tobuckle and tend to enter the arch of the shank on that side of the last.

In order to maintain, .during the wear of the shoe, the describedtransverse curvature and arched condition of the insole and outsole,after the shoe is completed to the point of applying the heel, theillustrated shoe is provided with rows of fastenings extendinglengthwise of the shank, the fastenings ex tending through and throughthe insole and outsole. These lines of fas'tenings act effectively tomaintain the transverse curvature of the shank throughout the wear ofthe shoe.

- Instead of these fastenings I may unite the insole and outsole fromthe ball to the heel breast in their entirety by other suitable means.

In the drawings,

Fig. 1 is aperspective view, partly in section, showing the interiorsurfaces of the-insole of a shoe embodying the present invention, theshoe being partly in section;

Fig. 2 is a sectional detail of the shank por- Fig. 4 is a sideelevation of a last used in making the shoe;

Fig. 5 is a perspective View showing the bottom surface of the lastillustrated in Fig. 2;

Fig. 6 is a view illustrating the insole blanks emplo ed andthe mannerin which they are cut rom the stock; and

Fig. 7 is a view of the plantar surface of the bones of a normal humanfoot.

Referring to Figs. 4 and 5, which represent a last 10, it will be seenthat there is upon the forepart of the last bottom a flat area boundedby a line having a curved part 12 and a straight part 14. In Fig. 5 aheavy broken line A, B, C, D has been drawn upon the last bottom toassist in describing various characteristics of the last. The line BCrepresents substantially the ball line or, as shown in Fig. 7 the linejoining the centers of the anterior ends of the first and fifthmetatarsal bones. The line 0-D is equal in length to BC, and the angleBCD is a right angle. It is found that the line C-D represents veryapproximately the direction of the first phalanges, that is, thedirection of the great toe. It will be noted that the area enclosed bythe triangle BCI) approximates the area enclosed by the line 12, 14, theshape of the triangle having been rounded and softened by the curvedline 12 and the straight portion 14 corresponding substantially to theball line of the last. The line 12 defines a shape forward of the ballline approximatin the shape "of the forepart of the last, and betweenthe line 12 and the periphery 16 of the forepart of the last is acrescent-shaped area 18 which slopes outwardly and upwardly from theline 12. This is best seen from Fig. 4 where the last is represented ashaving the flat surface of its forepart pressed upon a flat treadsurface F G. It will be seen that the peripheral line 16 extends fromthe ball line forwardly and upwardly in a gentle curve representingapproximately the spring of a usual last. This figure also indicates thevertical curvature of the crescent-shaped surface 18. It will be notedalso that the rear portion of the last is raised from the surface F-G 'adistance representing the height of the heel required for the last. Theflat area of the forepart bounded by the line 12, 14 represents the areaof the forepart of the foot which presses upon a fiat surface in the actof standing. The crescent-shaped- The line B-C represents approximatelythe line on which the forepart of the foot bends and the line 14parallel to it represents the ball line of the last and approximatelythe line along which the inso'le of the shoe has to bend in the act ofwalking. The line along which the insole has to bend is thereforestraight and maximum flexibility of the insole is assured since there isno transverse curvature of the sole at the ball line to interfere withits bending. This flat surface along the ball line B-C permits theanterior transverse arch of the foot to flatten out as it naturally doeswhen the toes are bent and pressure is applied to the ground in walkingbut it prevents this arch from bending too far as is the case when thesurface pressed on is concave as it frequently is instead of flat.

The line AB extends from about the center of the breast line representedby the forward edge of a heel plate 20, secured to the heel-seat of thelast, to the outer end B of the ball line and is a straight line, thesurface of the shank portion of the last having no vertical curvaturealong this line.

'It has been found that many of the important blood vessels, nerves andtendons of the foot lie adjacent to the vertical plane of the line A-B,and that any upward arch of the shank portion of the shoe along thisline tends to produce pressure upon these blood vessels, nerves andtendons and to interfere with circulation, sensation and normal actionof the foot muscles. For example, the tendon of a muscle on the innerside of the leg, called flexor longusdigitorum, passes down- Iwar'dlyand then horizontally through 'a groove in the astragalus boneshown at 21 (Fig. 7) and thence in a direction toward the outer end ofthe ball line. This tendon finally branches into four parts, one ofwhich is attached to the first phalange of each of the four smallertoes. The tendon is drawn by the muscle through the groove ,21 asthrough a pulley and the portion of the tendon running along the bottomof the foot tends to assume a-straight line parallel to the line AB. Itis also especially to be ,noted that the groove 22 in the plantarsurface of "the cuboid bone, through which the tendon of the leg muscleperoneus longus. passes to itspoint of attachment at 24 to the posteriorportion of the'first metatarsal bone, lies over this line. Since theline A-B is a straight line while the foot has a slight naturallongitudinal arch above this line, objectionable pressure upon thesetendons is avoided.

The normal action of the muscle peroneus longus helps in maintaining theposterior transverse arch of the foot and hence my construction, whichprevents pressure upon and interference with this tendon and hence withits muscle, avoids a frequent cause of foot trouble.

The heel-seat surface of a last represented by the plate 20 is made veryconvex so that a pronounced cup will be formed in the insole to receivethe heel portion of the foot and prevent lateral movement of the footwith re spect to the heel, thus avoiding running over of the heel.

A last having the characteristics described having been made, an insole26 is prepared. The insole, as indicated in Fig. 6, is made straighterthan the last; in fact, the insole may generally be substantiallybilaterally symmetrical with respect to its longitudinal median line.Preferably, however, a notch' 28 is made at the inner end of the ballline. The insoles are preferably cut by reversing the pattern or die endfor end for each cutting and placing it as close as possible to thepreviously cut edge. The result is that there is practically no loss ofmaterial except at the ends of the insoles. The material between theinner end of the ball line and breast line, as indion the bottom of thelast with its forepart coincident with that of thelast. Since the insoleis straigther than the last it will be necessaryto swingthe rear portionof the insole toward the inner side of the last to bring the heelportions over each other, and this act will cause the materialbetweenthe inner end of the ball line and the breast line to buckle toward theshank portion of the last. The last and insole are next placed in apress with the insole resting on a block of rubber or other yieldingmaterial. Sutficient pressure is then applied to the last to cause theinsole to conform perfectly to the bottom of'the lastand permanently toassume the shape of thelast shank from being carried forward from theball line and hence interfering with the flexibility of the sole. Bycutting out the insole as described the material between the heel andball on the inner side of the insole, which is usually wasted, is savedand'utilized to form, at no extra ex ense, an adequate shank sup-. portfor the oot, the only material wasted eing at the rounded ends of thepattern. The upper is then placed over the insole and last and the shoelasted about the shank and forepart in the usual manner by drawing themargin of the upper over upon the bottom of the insole and securing ittemporarily by lasting tacks driven through the upper and insole intothe wood of the last bottom. At the shank the lasting may be done in anyusual manner, for example, the insole and upper may be coated withcement so that when the cement has set and the temporary tacks arewithdrawn the upper will be held permanently in lasted position. A weltis attached with the upper to the lip or rib of the insole about theforepart, and the heel-seat portion of the upper is lasted in andsecured by tacks clinched upon thehecl plate 20. The temporary lastingtacks are now withdrawn and the upper trimmed at the forepart and, ifnecessary, filling material may be introduced. It is found, however,that, by reason of the upward and outward curvature of the area 16 aboutthe periphery of the last and insole, a space is provided for theaccommodation of the inseam so that little or no filling is 118685?sary, this construction being illustrated in Fig. 3. At the toe a smallamount of filling may be required in the channel to fill it up even withthe inseam. An outsole 29 is next applied to the shoe and is preferablyshaped to the shoe bottom in a manner similar to that employed forshaping the insole. The forepart of the outsole is next attached to thewelt byan outsole stitching machine in the usual manner. The last is nowwithdrawn from the shoe and through-and-through seams 30, 32 sewn alongthe margin of the insole to secure the insole, upper and outsoletogether. In addition, two other seams 34, 36 are sewn through the twosoles for the purpose of causing the transverse curvature of the shankportions of the sole to be maintained. Instead of the seams 34, 36,other means of fastening may be employed, the purpose being to preventrelative movement of the insole and outsole or the bulging of oneoutwardly with respect to the other such as would be necessary if thistransverse curature of the insole were flattened out while the soleswere held by the seams 30,32.

The novel features exemplified by the last herein illustrated have notbeen claimed herein since they are claimed in a divisional application,Serial No. 384,315, filed August 8, 1929.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. A shoe having an insole the forepart of which has a flat areaextending from a line at the rear of the ball line of the foot anddimmishing in width transversely of the shoe to a point between thegreat toe and the second toe, the surface of the insole outside of andforward of said area extending upwardly and outwardly to afford abearing surface for the outer portions of the toes.

2. A shoe having an insole the forepart of which has a flat, triangularareaextending from the ball lineat the rear of the enlargements at theforward ends of the first and fifth metatarsal bones to a point betweenthe great toe and the second toe, said trian- .gular area beingsufficient to afford support for the portion of the forep-art of thefoot first touching the ground including substantially the area coveredby the inner phalanges, the toe portion of the insole outside the said3. A shoe having an insole shaped to extend in a straight line from themid portion of the breast line to the outer end of the ball line for thepurpose of preventing pressure on the blood vessels, nerves and tendonsextending glong near the surface of this portion of the cot.

4. A shoe having an insole and outsole shaped to extend in a straightline from the mid portion of the breast line to the outer end of theball line for the purpose of preventing pressure on the blood vessels,nerves and tendons extending along near the surface of this portion ofthe foot.

5. A shoe having an insole and outsole shaped to form a concave troughfor the shank portion of the foot, and more than two longitudinallyextending rows of fastenings extending through and through the shankportions of both soles to maintain the interiorconcavity and exteriorconvexity of the shank portion ofthe sole.

6. A shoe having an insole and outsole shaped to form a concave troughfor the shank portion of the foot, and means for maintaining theinterior concavity and exteiior convexity of the shank portion of the soe.

'7. A shoe having an insole and outsole shaped to extend in a straightline from approximately the mid portion of the breast line to the outerend of the ball line and shaped transversely of that line to form aconcave trough for the shank portion of the foot, and

means for maintaining the interior of concavity and exterior convexityof the shank portion of the sole.

8. A shoe having a shank portion formedby inner and outer soles, saidshank portions being transversely curved to form a concave troughlengthwise of the foot, the bottom of said t ough being straight andextending from the center of the breast line to the outer end of theball line, and means for stiffening the soles to maintain the transversecurvature.

9. A shoe having a shank portion formed by inner and outer soles, saidshank portion being transversely curved to form a concave troughlengthwise of the foot, and throughand-through fastenings extending inlines lengthwise of the shank to stiffen the soles against reduction ofthe transverse curvature.

10. An insole for shoes having excess material on its inner side theextent of which outwardly of the insole is substantially defined by astraight line connecting the inner u and flexor longus digitorummuscles. I

ends of the ball line and the breast line, said excess material beingmolded into a shape to enter the longitudinal arch on the inner side ofthe foot, said insole having in its edge a 5 sharpnotch the apex ofwhich is located adj acent to the inner end of the ball line to preventthe stiflening effect due to saidmolding from extending beyond the ballline and the ball line being straight from side to side to m afiordmaximum flexibility of the insole at the ball line. a

11. An insole for shoes havin a fiat and substantially triangular areaon 1ts fore artwith an upwardly and outwardly exten ing margin outsideof said area.

12. An insole for shoes having its inner face straight along the linefrom the center of the breast line to the outer end of the ball line,the remaining portions of the shank being transversely concave' 13. Aninsole for shoes having its inner surface straight along a line fromapproximately the center of the breast to the outer end of the balllineand having a substantially flat area from the ball line forward atthe I central portion of the forepart.

14. An insole for shoes having its inner face straight along the linefrom approximately the 'center of the breast line to the so outer end ofthe ball line, the remaining portions of the shank being transverselyconcave and the heel-seat portion being deeply, cupped. I a 15. Aninsole-for shoes having in the inner as face of the shank-plortion agroove or trough the bottom of whic extends in a straight line from thecenter of the breast line to the outer end of the ball line, said groovebeing for the purpose of avoiding excessive pressure on the 1 an nervesof the foot, on'the external plantar arteries supplying the plantarsurface of the foot, and preventing interference with the action of thetendons of certain muscles, particularly that of roneuslo 16. An insoleor shoes having in the. in-

ner face of the shank portion a groove or trough the bottom. ofwhich-extends in a straight line from the center of the breast line .tothe outer end of the ball line, said groove so being for the purpose ofavoiding excm pressure on the nerves of the'lfoot' onthe externalplantar arteries supplying the plan! surface of the foot and preventinginterference with the tendons of the peroneus longus In testimonywhereof I have signed myname to this specification. PAUL F. W.- O.KRIPPENDORF,

